Radon poisoning

The word poisoning brings a picture with it: a sudden exposure, quick symptoms, a diagnosis and a treatment. Very little of that fits radon. The table sets out, point by point, what EPA, CDC and WHO actually describe.

Two things follow. First, there is nothing to watch for day to day, so waiting for signs is not a strategy. Second, the two things that set the risk, the level in the air and the time spent breathing it, can both be measured, and the level can be changed.

Radon's harm comes from radioactivity, not from a chemical reaction in the body. ATSDR describes radon as a naturally occurring, radioactive, noble gas that is odorless, colorless, and tasteless, and explains that since radon is a noble gas, it releases from any chemical bonds that attach it. What matters for health is what it turns into. Radon progeny, in ATSDR's words, is the term given to those radioactive atoms with short half-lives into which radon quickly decays.

Why the dose and the years matter

ATSDR states the general rule for any hazardous substance: the effects of exposure depend on the dose, the duration, how you are exposed, personal traits and habits, and whether other chemicals are present. For radon it is specific: the greater your exposure to radon, especially if you smoke cigarettes, the greater your chance of developing lung cancer. That is why radon risk is a matter of levels and years, not of a single exposure.

How scientists know radon causes cancer

EPA says WHO, the National Academy of Sciences, the US Department of Health and Human Services and EPA have classified radon as a known human carcinogen, because of the wealth of biological and epidemiological evidence. The largest study EPA cites was led by the National Cancer Institute (NCI) and examined the data on 68,000 underground miners; EPA says these miners are dying of lung cancer at 5 times the rate expected for the general population, and that the lung cancer risk in miners has been documented at exposure levels comparable to those which occur in homes. The full evidence is in radon and lung cancer.

EPA, CDC and WHO describe no symptoms of radon poisoning while exposure is happening. Radon gives no sensory warning: WHO says it has no smell, colour or taste, and CDC calls it an odorless and invisible radioactive gas. The disease it is linked to does not announce itself early either.

Radon poisoning symptoms: what CDC says

CDC's radon page is direct about the timeline. It takes many years for lung cancer to develop, and most people don't have symptoms until lung cancer is advanced, when it is harder to treat. CDC's conclusion is that it is important to take steps to reduce radon exposure throughout your life to help prevent lung cancer. CDC describes no separate short-term illness from radon.

Signs of radon poisoning people look for

Headaches, tiredness, coughing, nausea and allergy-type reactions are the signs people ask about. None of them is described by EPA, CDC or WHO as an effect of radon exposure, and WHO states that no health effects other than lung cancer have been established to date. If you have any of these symptoms, there is no known reason to put them down to radon, and a doctor is the person to see. For each complaint in turn, see radon symptoms.

What radon does is raise the risk of lung cancer. EPA says radon is the second leading cause of lung cancer overall and, according to EPA estimates, the number one cause of lung cancer among non-smokers. EPA estimates radon is responsible for about 21,000 lung cancer deaths every year, and that about 2,900 of those deaths occur among people who have never smoked. CDC gives the same ranking: radon is the second leading cause of lung cancer deaths in the United States after cigarette smoke.

WHO describes the effect worldwide. It estimates that radon causes between 3% and 14% of all lung cancers in a country, depending on the national average radon level and smoking prevalence, and that the risk of lung cancer increases by about 16% per 100 Bq/m3 increase in long-term average radon concentration. The risk was first seen in uranium miners exposed to very high concentrations, but WHO is clear that ordinary homes matter too:

Effects of radon poisoning beyond the lungs

WHO states that no other cancer risks or other health effects have been established to date, although inhaled radon can deliver radiation to other organs at a much lower level than to the lungs. Radon in drinking water is a related worry. WHO reports that epidemiological studies have not confirmed an association between drinking water containing radon and an increased risk of stomach cancer, and EPA says most of the risk from radon in water comes from radon released into the air when water is used for showering and other household purposes. See radon in water for testing a well.

Radon poisoning statistics

These are population estimates, not counts of diagnosed cases, and none of them is a reading of any home. NCI adds that exposure to the combination of radon gas and cigarette smoke creates a greater risk of lung cancer than exposure to either factor alone.

People who ask how long it takes to get radon poisoning are asking about exposure time. There is no set number of hours, months or years after which radon becomes harmful. Risk rises with both the level and the time: EPA says your chances of getting lung cancer from radon depend mostly on how much radon is in your home, the amount of time you spend in your home, and whether you are a smoker or have ever smoked.

Radon exposure: how long before it matters?

There is no set waiting period and no point after which it is too late to act. CDC says it takes many years for lung cancer to develop and recommends reducing radon exposure throughout your life. EPA notes that the time between exposure and the onset of the disease may be many years, and says you will reduce your risk of lung cancer when you reduce radon levels, even if you have lived with an elevated level for a long time. Because EPA ties risk to time spent in the home, a short stay in a house with a high level is a small part of a lifetime's exposure, while years of living with it are a much larger part.

EPA's risk chart shows how level and lifetime exposure combine. EPA estimates that if 1,000 people who never smoked were exposed to 4 pCi/L over a lifetime, about 7 could get lung cancer; at 20 pCi/L, about 36 could. For 1,000 people who smoked, the figures are about 62 and about 260. These are population estimates for lifetime exposure, not a prediction for any one person. The full chart is in radon and lung cancer.

How long before you get sick from radon?

There is no set number of days or months. CDC's radon feature says it may take years before health problems appear, and that radon-associated lung cancer can be prevented by limiting exposure to radon in indoor air. EPA notes that people are always exposed to some radon, because radon comes naturally from the earth, and NIEHS says it is not possible to avoid radon completely. The aim is a lower level over the years, not zero. Radon symptoms sets out the timeline in more detail.

WHO says that for most people the greatest exposure to radon occurs in the home where people spend much of their time, though indoor workplaces may also be a source of exposure. The very highest levels are elsewhere: WHO says radon concentrations are higher indoors and in areas with minimal ventilation, with highest levels found in places like mines, caves and water treatment facilities. EPA says people are exposed to radon primarily from breathing radon in air that comes through cracks and gaps in buildings and homes.

Limits for miners

For people who work in mines, ATSDR reports that the Mine Safety and Health Administration (MSHA) has adopted an exposure limit of 4 Working Level Months (WLM) per year. For homes, the benchmark is EPA's guidance on the level in the air, covered in radon limits.

For most people, WHO says, the greatest exposure to radon occurs in the home. EPA's Citizen's Guide explains why: radon comes from the natural decay of uranium found in nearly all soils, moves up through the ground to the air above and into the home through cracks and other holes in the foundation, and the home traps it inside, where it can build up. Radon from soil gas is the main cause of radon problems, EPA says; sometimes radon enters through well water, and in a small number of homes the building materials give off radon.

Read this figure as textHide the text version

1. 1Cracks in solid floors
2. 2Construction joints
3. 3Cracks in walls
4. 4Gaps in suspended floors
5. 5Gaps around service pipes
6. 6Cavities inside walls
7. 7The water supply

• Cracks in solid floors
• Construction joints
• Cracks in walls
• Gaps in suspended floors
• Gaps around service pipes
• Cavities inside walls
• The water supply

Any home may have a radon problem, EPA says: new and old homes, well-sealed and drafty homes, and homes with or without basements. WHO says levels are usually higher in basements, cellars and living spaces in contact with the ground, which is why worry about radon poisoning so often centers on the basement. The radon map and location reports show what is predicted for an area, but EPA is clear that while radon problems may be more common in some areas, the only way to know about your home is to test.

Radon poisoning test: test the air, not the body

People ask what test would show radon poisoning. ATSDR's answer is that radon in human tissues is not detectable by routine medical testing. Some radon progeny can be detected in urine and in lung and bone tissue, but these tests cannot tell how much radon you were exposed to, nor can they be used to predict whether you will develop harmful health effects. Radon exposure is estimated by measuring radon levels in the air. CDC says the only way to know if you have unsafe levels of radon in your home or office is by testing. Testing is the only way to know the radon level in a specific building.

If you have questions about your own health, including any screening, a doctor is the person to ask. For concerns about exposure to hazardous substances, ATSDR says it can also tell you the location of occupational and environmental health clinics, which specialize in recognizing, evaluating, and treating illnesses resulting from exposure to hazardous substances.

1. 1

   Test the lowest lived-in level

   EPA says all radon tests should be taken for a minimum of 48 hours. Keep windows and outside doors closed, apart from normal entry and exit, from at least 12 hours before a test of less than four days. See how to test.

2. 2

   Read the result

   EPA recommends fixing a home when the radon level is 4 pCi/L or higher. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. The interpreter explains your number.

3. 3

   Confirm a high first result

   EPA's steps: follow a high short-term result with a long-term test, or with a second short-term test if you need results quickly. If the first result is more than twice EPA's 4 pCi/L action level, take the second short-term test immediately.

4. 4

   Have it fixed by a qualified professional

   CDC: lowering high radon levels requires technical knowledge and special skills, so rely only on a qualified professional. Your state radon office can help find one, and the directory lists mitigation contractors.

5. 5

   Retest

   Test again after any repairs to be sure they worked, and retest every two years to be sure levels remain low.

Radon poisoning treatment: lower the exposure

The response to radon exposure is less radon. EPA says the method primarily used is a vent pipe system and fan that pulls radon from beneath the house and vents it to the outside, known as a soil suction radon reduction system, and that some radon reduction systems can reduce levels by up to 99%. WHO reports that passive systems of mitigation can reduce indoor radon levels by more than 50%, and that adding radon ventilation fans reduces levels further. CDC cautions that natural ventilation, such as opening windows, is only a temporary strategy. See how radon mitigation works.

Read this figure as textHide the text version

1. 1Soil gas drawn from beneath the slab
2. 2Suction point through the slab
3. 3Vent pipe
4. 4Fan, outside the living space
5. 5Discharge above the roofline

CDC's advice on who should do the work is plain: if your home radon level is at or above 4 pCi/L of air, contact a qualified professional to install a radon reduction system, because contractors who do not specialize in radon reduction could make the problem worse. On cost, CDC says most homes can be fixed for about the same cost as other common home repairs. ATSDR notes that EPA also says radon levels less than 4 pCi/L still pose a health risk and can be reduced in many cases.

Radon treatment for well water

When radon comes in with private well water, the treatment is for the water. WHO says straightforward and effective techniques exist to reduce the concentration of radon in drinking-water supplies by aeration or using granular activated carbon filters, and that normally a higher radon dose is received from inhaling radon compared with ingestion. See radon in water.